Method of making tubular articles



Oct. 17, 1933. H. w. KRANZ r-:r AL

METHOD OF MAKING TUBULAR ARTICLES FiledOct. 24. 1929 a 5. MW mzvm m Nn 7.T A K:

Patented Oct. 17, 1933 METHOD OF MAKING TUBULAR ARTICLES Harry W. Kranz, Lakewood, and Homer L. Mueller, Cleveland, Ohio, assignors to The Cleveland Welding Company, Cleveland, Ohio, a corporation of Ohio Application October 24, 1929. Serial No. 402,042 3 Claims. (01. 29-156) This invention, as indicated, relates to the method of forming tubular articles and has specific reference to the method of forming such articles of relatively small diameter with comparatively thick shells, although the methods comprising our invention are applicable to tubular articles of larger diameter as well.

The method commonly employed in the forming of tubular articles is to pass the blank from which such article is made through a suitable bending machine in which the blank is substantially circularized by passing between suitable rollers. This method, however, is not applicable to the forming of tubular articles of a relatively small diameter, since the small diameter prevents the employment of rolls in the manner common to machines for forming tubular articles of a relatively large diameter. Due to the relative thickness of the wall of small tubular articles to the diameter thereof, the method of forming such small articles from substantially flat blanks resolves itself into a method employing dies instead of the ommon type rollers.

Heretofore no method of forming tubular articles of relatively small diameter and thick walls has been devised in which the finished article does not have portions thereof which are different in contour from that of the finished article. The method comprising our invention insures the accurate forming-of each part of the shell of the article to correspond to the desired finished form.

To the accomplishment of the foregoing and related ends, said invention, then, consists of.

the means and steps hereinafter fully described and particularly pointed out'in the claims; the annexed drawing and the following description setting forth in detail certain means and one mode of carrying out the invention, such disclosed means and mode illustrating, however, but one of various ways in which the principle of the invention may be used.

In said annexed drawing:--

Fig. 1 is an isometric view of a form of blank from which the tubular article is to be made; Fig. 2 is an isometric view showing curved ends formed on the blank shown in Fig.- 1; Fig. 3 is a perspective view of the blank shown in Fig. 2 after such blank has been further deformed; Fig. 4 shows the blank of Fig. 3 with the adjacent edges welded; and Fig. 5 shows the article illustrated in Fig. 4 with the flash or burr removed.

Referring more specifically to the drawing and more especially to Fig. 1, the blank 1 here shown is of the common type used in the manufacture of tubular hub shells for wire spoke wheels and consists of a substantially fiat medial portion 2, bent ends 3-and 4, respectively, and a longitudinal ridge 5. The next step in the method comprising our invention is to curve the terminal portions 6 and 7 of the blank 1 into arcuate portions having radii substantially equal to the radius of the article to be formed. The next step, as illustrated in Fig. 3, is to form the medial portion 8 into arcuate form having a radius substantially equal to the article to be formed.

The article as illustrated in Fig. 3 then has its edges 9 and 10 brought into abutting relation and suitably welded or otherwise joined to form the finished article. If the shell is welded a burr 11 may result, as shown in Fig. 4, which is then removed by suitable grinding or cutting to form a substantially smooth seam 12, as illustrated ,in Fig. 5.

It will be understood that the blank 1 from which the tubular article is made may be either pre-formed or may be formed to the proper size and shape as a part'of the method comprising this invention. It will further be understood that the general contour of the blank 1 will, to a great extent, correspond to the contour of the shell of the article to be formed by the method comprising, our invention. I

The various steps of the forming process, as

.heretofore outlined, may be carried on in mech- I anism substantially as the following: 'The blank,

as illustrated in Fig. l, which for the purposes of this description is considered to be pre-formed and cut to the desired length, such length depending upon the circumference of the article to,be formed, is then inserted in a press having dies which form the ends 6 and '7 into portions having the contour of segments of the finished article. This pressing of the ends of the blank 1 can be accomplished very readily when the blank is in the form illustrated in Fig. 2 since the ends are thus sufilciently spaced apart to permit the action thereon by dies of sufficient strength to form each portion ,of such ends into truly cylindricalform. The, medial portion 8 of the blank is then readily accessible to the action of another pair of dies which form such medial portion 8 also into true cylindrical form, thereby effecting a proper formation of the entire periphery of the shell. 'If the edges 9 and 10, after the completion of ,the above outlined pressing. operation, are found to be somewhat spaced apart this gap may be closed'by subjecting the shell to an additional set of complementary dies having the same circumferential con-- tour as the article to be formed, thereby not only instu'ing the closure of the gap between the edges 9 and 10, but also a compliance of every portion of the shell to the desired circumferential contour. After the adjacent edges 9 and 10 have been brought together they may be suitably welded in the common type of welding apparatus for such articles, especially the mechanism described in co-pending application Serial No. 290,959, filed July '7, 1928. After such welding has been completed, the flash or burr 11 necessarily incidental to such welding may be sheared ofi or otherwise removed to present a. smooth seam and the article is then in finished form or in shape for further action not forming a part of this invention.

A further description of the methods comprising our invention is deemed unnecessary since the various steps may be accomplished by diverse means and the general contour of the finished article, as well as the blank from which such article is made, may depart from that alluded to in this description without a departure from straight blank, curving the ends of said blank to a radius equal to that of the finished article, said curved ends being tangential to the body of said blank, bending the medial portion of said blank to the same radius of curvature and about the same center as that ofthe finished article, whereby said end portions and said medial portion are arcuately continuous and then bringing together the edges of said curved ends.

2. The method of forming tubular articles which comprises the forming of curved ends on a preformed blank, said curved ends being tangential to the body of said blank, bending the medial portion of said blank to the same radius of curvature and about the same center as that of the finished article, whereby said end portions and said medial portion are arcuately continuous and then bringing together and welding the edges of said curved ends.

3. The method of forming tubular articles having a variable longitudinal contour, said method comprising the provision of a preformed blank having a length substantially equal to the circumference of the article to be formed, bending the ends of said blank to a radius of curvature substantially equal to the radius of the article to be formed, said curved ends being tang'ential to the body of said blank, bending the medial portion of said blankto the same radius of curvature and about the same center as that of the finished article, whereby said end portions and said medial portion are arcuately continuous and then bringing together and welding said ends.

HARRY W. KRANZ. HOMER L. MUELLER. 

